By-pass for pumping apparatus



Jan. 2, 1962 L. M. NECHINE 3,015,279

BY-PASS FOR FUMPING APPARATUS Filed Sept. 26, 1958 3 Sheets-Sheet 1 hl ll\ Jan. 2, 1962 M. NEcHlNE 3,015,279

BY-PASS FOR PUMPING APPARATUS Filed Sept. 26, 1958 3 Sheets-Sheet 2 Jan.2, 1962 l.. M. NECHINE 3,015,279

BY-PAss FOR PUMPING APPARATUS Filed Sept. 26, 1958 3 Sheets-Sheet 5Filed Sept. 26, 1958, Ser. No. 763,658 6 Claims. (Cl. 103-11) 'Thisinvention relates to pumping apparatus and is particularly concernedwith a novel ilow system through which sewage may be delivered to asewage basin while pumps are operating to Withdraw sewage through saidsystem Vfrom said basin.

It has been customary to provide a single ow system comprising a pumpand apump by-pass valve so arranged that sewage delivered to the systemthrough a main sewage inlet may ow through the system and around .thepump to the basin when the pump is idle. In such systems the pump oftenwasdesigned for greater lift than required by actual conditions, ordischarge pressures changed as a result of -varying operating loads. Thevariations in the pressure ofthe pumpow create greater or lessdifferential pressures on the upstream and downstream sides o f theby-fpass valve. These diierential pressures affect the by-pass valve ina manner to cause unstable operation of said by-pass, valve, withresultant leakage and loss of pressure in the pump ow.

In accordance with the present invention the ow of sewage or otherliquid to and from the sewage basin is through a ow system thatpreferably includes two ,or more pumpsfand associated by-pass valvesIselectively operated in such manner that any or all of the pumps mayoperate to pump sewage from the basin without impeding the flow ofsewage to the basin. For yconvenience, the system comprising theinvention will be described as a two-pump installation, but it will beunderstood that it is not limited to two pumps, and maybe used with asingle pump or with more than two pumps.

Separate pump control means are provided to sequentially start and stopthe pumps. The operation of the control means is such that when theliquid in the basin reaches a predetermined high level, a first pump isoperated to pump liquid from the basin. Operation of this pump closes arelated by-pass valve and a Vcheck valve in the inlet conduit, thusstopping the flow of'sewage therethrough to the basin. Should thecontinued ilow of liquid to the basin through the other inlet conduitand the other by-pass valve result in the liquid level continuing torise, a second pump is operated. Operation of the second pumpautomatically closes a by-pass valve related thereto and a check valvein its inlet conduit. However, when both pumps are being operated,sewage may continue to tlow to the basin from the main sewage inletconduit through a bar box provided therein.

The dual-pump system herein described includes two reverse-flow pipes orconduits in direct ilow communication with a main sewage inlet conduit.Eachpipe has a fitting provided with a by-pass valve and connected to acommon conduit, leading directly into the sewage collecting basin so asto permit the free and uninterrupted United States atent O inow ofliquid through the inilow pipe to said basin'when 1 both lpumpsare idle.When both pumps are operating to withdraw liquid from the basin, saidwithdrawn liquid is owed under pressure through the pump by-passiittings in such manner as to automatically close the -by-pass valve ineach fitting and the check valve in each inlet conduit. rl`he liquid isthen owed through the reverse-flow conduits in a direction reverse tothat of the inflow, and into discharge pipes, one of which is in llowcommunication wth each reverse-dow conduit, for disposal.

When the check valves in both inlet conduits and the by-pass valves inboth fittings are closed by the operation ice of both pumps, the inilowof liquid in the main sewage inlet :line backs up therein and overilowsa bar box in lsaid line. The liquid spilling over the weir sides of thebar box is delivered directly into the basin. When only one of the pumpsis operating, the-ow from said purmp is through the related by-passiitting as described hereinabove, and the ow of incoming liquidcontinues through the vby-pass fitting connected with the pump that isidle. Suitable screens and strainers are arranged in the flow system tointercept sewage solids and thus prevent such solids from entering thebasin and being subsequently withdrawn through the pumps.

Chatten'ng of the valve elements in the by-pass valves, `and resultantleakage and loss of pressure in the pump flow, is avoided in the presentflow system byjconnecting the by-passI passageway of Aeach valve indirect flow communication with the sewage basin at -a point below thelowest level of liquid therein, thereby providing a water seal for eachby-pass valve.

The "structure by means of which the above'noted and other advantages ofthe invention-are attained will be described in the followingspecication, taken in conjunction withthe accompanying drawings,'showinga preferred embodiment of the invention, in which:

-FIGURE 1- is a vertical transverse section view 'of a collecting basin,taken substantially on line i1-1 of FIG. 2, illustrating a sewagepumping apparatus embodying my invention connected therewith, with partsbroken away to facilitate illustration;- f

FIG. 2 is an elevational view of the apparatus as viewed from the leftside of FIG. l;

FIG. 3 is a -top plan view of the apparatus; and

FIG.4 `is* an enlarged sectional view of `one of the pump by-passlittings. l

Referring now to the accompanying drawings, and -particularly to FIG. 1,there is provided a sewage collecting basin 11, into which sewage forexample, is delivered for subsequent pumping to a suitable place fordisposal by means of the novel pumping apparatus associated with it.`Sewage or other liquid containing solids, suchas debris, abrasives,etc., enters thelsystem from' an influent conduit external of thestructure disclosed, through a main sewage inlet conduit 12. Theinflowing liquid passes through a diversion fitting 13, through a pairof conduits 14, 15, each containing a normally open service valve 16 anda check valve -17, and into reverse ow conduits 1S and 19 respectively.A conical screen 21 is provided in each of the conduits 18, V19 forscreening out solids in the incoming liquid owing'through said conduitsinto valve controlled pump by-pass ttings 22, 23 respectively. Each ofthese lay-pass fittings has a leg 24 in direct flow communication with aY-tting 25 connected to a conduit 26 leading into the interior of thecollecting basin 11, adjacent to its bottom. A normally open servicevalve 27 may be provided in the conduit 26.

The other leg 2S of by-pass tting 22 is connected to the dischargevolute 29 of a pump 31, whereas the correspondingleg 28 of by-passfitting 23 in connected to the discharge volute 32 of a pump 33. Thesepumps 31 and 33 may be of any conventional construction, and each hasassociated with it anelectric or other suitably driven motor 34, 35respectively, having its shaft connected to the impeller of the relatedpump fordriving the same. The suction inlets to said pumps are connectedto pipes 36, 37 respectively, which are in direct flow communicationwith the interior of the basin 111, also adjacent to its bottom. y Y eAs noted hereinabove, when both pumps v131, 33 are idle, inowing liquidpasses freely through both pump bypass fittings 22 and 23, throughY-tting 25 and then into the basin.` The by-pass fittings 22 and 23 areidentical, hence the following specic description of one is duitsassociated with the pump that is idle.

i l, both check valves and both `(and Vthe Yinflow of liquid through theflow system is equally applicable to the other. As best shown in FIG. 4,pumpby-pass iitting 23 has a valve element 38 `mounted adjacent to theby-pass passageway 39 in plate 41 se- Y cured to the end of its leg 24.The valve element 38 is in the form of a disc having a top wall 42 whichseats on o ow from entering the diversion fitting 13. When both a valveseat preferably formed by an annular member 44 -which'is fitted intosaid passageway, as by a drive tit. The top wal1-42 preferably has a cupshape, and its concave side is .in the direct line of How from the pumpwhen Vthe valve element is in the open position shown.

-The valve element 38 is pivotally mounted along one -ofitssides on abolt or pivot pin 45 for swinging movernient into open and closedpositions. A curved skirt or shroud `portiondt on said valve elementoverlies a helical spring 47, `which surrounds the pivot pin. Spring 47has one end 48 anchored in the plate `41 and its other end 49 engaged inan opening 51in the valveV element. `Itv is manifest from the drawingsthat the shroud 46 protects they spring against the accumulation thereonof any small solids which might pass 'the strainer and thus `is atorsion spring `and it is Vprimarily adapted to maintain valve element38 in the normally open position shown.` AIt functions Valso as ananti-slam device when the low through the fitting is sharply reversed,vas when theassociated pump is started. Y'

The operation, insofar asthe assembly hasfbeen described, is such thatwhen the liquid in basin 1 1y is at a predetermined low level, as shownYat 52, the motors and basin raises suciently to cause an enlargement 54on its `rod 55 to engage and Aclose a normally'open switch 56,

controllingV the operation of one of the pump Ymotors 34 Operation ofone of said motors and its pump will, in a'ma'nner to be describedpresently, cause the related check valve and by-pass valve to closewithdraws liquid from the basinand dischanges it at a suitable placeVfor'disposal. However, inasmuch as only one of the pumps is operating,incoming sewage will continue to enter the basin through the systemv ofinow con- Should the inilow'of liquid be in excess ofthe capacity of thepump ythat is operating, the level of the liquid will continue to risein the basin, the float will be raised further and its rod enlargement54'will then engagel and close a second `normally open switch 57controlling operation of the secondV pump so as to place said pump inoperation. VWith both pumps operating Vto withdrawliquid'from the basin,by-pass valves are closed,

prevent successful operation of the valve. The spring 47 while the pumpof these check valves are closed, the inow of liquid vthrough the flowsystem is stopped, thus causing incoming sewage to back up in the mainsewage inlet conduit 12 and spill over the weir sides of a bar box 62mounted V in said conduits and into the basin. The bar box 62 isstopped. When the yliquid level in the basin recedes, the Y Ypumpspasses through .the respective by-pass fittings 22,

23, up through the' strainersY V21, carrying with it the solid matteraccumulated around the strainers, and is discharged with the solidmatter through respective discharge pipes 58 and 59 (FIG. 2). Ifdesired,a service shut-,off valve 6 1 may be provided in each o f'the pipes 36,37A.

V The pressure of the pump` flow in the conduits 18 duit connecting saidprovided with a screen 63 to prevent solids of objectionable size Ifrompassing over the sides 'of the box intov Y basin V11. When the pumpsstop, and the sewage resumes its normal ow, the liquid owing throughVthe main inlet conduit carries the solids from the underside'of screen63 through conduits 18 or 19 Vto strainers 21.

Because of the use of two or Vmore pumps and their related ow systems,the ow capacity and lift power of each pump may be much smallerl thanthat 'required of a single pump, owing to the periodic operationalrequirements arising from varying volumes of liquid required to be drawnfrom the basin. As a result there is less Vwear on the pumps and theirmotors, Yand maintenance and operational costs are reduced.vFurthermore, the lowest permitted level of liquid in the Vbasin ismaintained above Vthe level of the' by-pa'ss valve 'elements s'oas toprovide a water seal on the'suction side by Ythe by-pass valveswhenptheir related pumps are operating.V reduces Vthe possibility .ofvalve leakage, valve chatter, and unstable operation of the pumpsthrough loss of pressure on their discharge side. g

Although I have described a Vpreferred embodiment of my invention inconsiderable detail, it 'willbe understood that the description' thereofis intended toV be illustrative, rather than restrictive,V as manydetails ofl the structure may be modified or changed without departingfrom the spirit or Vscope of the invention. Accordingly, l do not desireto be restricted to the exact construction described.

1. In combination, a sewage basin, a'niain inlet conduit bridging thebasin, a diversion fitting on said conduit, said'fitting comprising aplurality of branches, a reverse flow conduit in "flow communicationwith each branch of said diversion fitting, a pump operatively connectedto each reverse flow conduit, eaclil of said pumps being Vspaced Ifromsaid sewage basinand operable to pump liquid from Vthe basin through itsrelated reverse flow conduit, a motorfor operating each pump, a pumpby-pass passageway inl each reverse. flow conduit, a common con.-by-pass passageways with the basin, a valve element in each by-passpassageway, means to hold each `valve element in open position to permitilow of liquid to the basin through the related reverse flow conduitwhile the related pump is idle, each of Vsaid valve elements being movedautomatically into closed position when the related pump is started,separate norm-allyopen switches for each motor, Vmeans for successivelyclosing said switches in response to rises of the liquid level in thebasin, the operation of Yeach pump stopping the ilowof liquid to thebasin through its related reversefilow conduit, and an overflow bar boxin thejmain inlet conduit through which liquid may spill into the basinwhen all of the pumps are operating. p' l 2. In combination, a basin,`reverse ow. conduits through which liquid is iiowedin one direction tothe basin and in an opposite directionifrom the basin, a pumpvoperatively connected to eachy reverse ilowconduit and Y passage'wayswith the basin, saidV by-pass'passageways and the connectingV conduitbeing arranged below the lowest liquid level in said basin to maintainkliquid in Vsaid connecting conduit and by-pass passageways at alltimes, a.

valve element in each passageway, means normally holding said Valveelements in open position to permit liquid ilow to the basin throughany' reverse ow conduit when the related pump is idle, said valveelements when in open position each lying in the path of liquid iiowtrom the related pump when said pump is operating and being sodimensioned as to be moved by said flow into closed position against theaction of said holding means, and means responsive to diierentpredetermined high liquid levels in said basin to selectively operatesaid pumps while permitting liquid to flow into the basin throughreverse llow conduits related to pumps not in operation, the by-passpassageways related to said idle pumps, and said connecting conduit.

3. in combination, a basin, a main inlet conduit, reverse flow conduitsin flow communication with said main inlet conduit, a strainer in eachreverse ilow conduit to separate solids from liquid ilowing to thebasin, a pump opera- -tively connected to each reverse ow conduit, meansfor operating each of said pumps to pump liquids from the basin throughthe related conduit, said means being adapted to operate any of saidpumps individually or simultaneously, a pump by-pass passageway in eachreverse ow conduit, a common conduit leading from said passageways tosaid basin, a valve element in each passageway, means for automaticallymoving each of said valve elements into closed position to preventliquid flow through its passageway to said basin when the related pumpis in operation, and means for permitting screened sewage to flow fromsaid main inlet conduit directly into said basin when all of the pumpsare operating.

4. In combination, a basin, a main inlet conduit, a pair of reverse ilowconduits in flow communication with the main conduit, a dischargeconduit in iiow communication with each of said reverse flow conduits, apump operatively connected to each reverse flow conduit, means foroperating each of said pumps individually or simultaneously to pumpliquid from the basin through the related reverse ow conduit and to therespective discharge conduits, a pump by-pass passageway in each reverseilow conduit, a common connecting conduit leading from said passagewaysto said basin, a valve element in each passageway, a spring operativelyconnected to each of said valve elements, each of said springs beingadapted to move the valve element to which it is operatively connectedautomatically to open its passageway when the related pump is idle,means for automatically moving each of said valve elements to close itspassageway when the related pump is in Operation, said valve elementsand said connecting conduit being below the lowest level of liquid insaid basin to maintain a liquid seal at each of 6 the valve elementswhen it is in closed position during operation of the related pump.

5. in combination, a basin, conduits for liquid ilowing in one directionto the basin and in an opposite direction from the basin, a pumpoperatively connected to each conduit, means for operating any of saidpumps individually or simultaneously to pump liquid from the basin, apump by-pass passageway in each conduit, a common conduit connectingeach of said by-pass passageways with said basin, a valve element ineach passageway for opening and closing the passageways, spring meansconnected with each valve element to hold it in open position when therelated pump is idle, each valve element when in open position being inthe path of liquid ow from the related pump and being so dimensioned asto be directly responsive to said flow to be moved into closed positionagainst the action of said spring means when the related pump is inoperation, said by-pass passageways and said connecting conduit beinglocated below the lowest level of liquid in said basin so as to maintaina liquid seal at each ot the valve elements when it is in closedposition during operation of the related pump.

6. ln combination, a basin, a main inlet conduit, a pair of reverse llowconduits communicating with said main inlet conduit, a common connectingconduit communicating with both of said reverse flow conduits and saidbasin for iiowing liquid to said basin, a pump operatively connected toeach of said pair of reverse flow conduits, each of said pumps beingspaced from said basin and operable to pump liquid through its relatedreverse flow conduit in the opposite direction, means to operate saidpumps individually or simultaneously, a by-pass fitting in each of saidreverse ow conduits adjacent said pumps, liquid being adapted to flowfrom said main inlet conduit through one of said reverse ilow conduitsand its by-pass tting when the related pump is idle, a valve in each ofsaid bypass iittings to prevent ow of liquid from either of said reverseilow conduits to said connecting conduit when the related pump is inoperation, and means for flowing liquid from said main inlet conduitdirectly to said basin when both of said pumps are operating, saidvalves and said connecting conduit being below the lowest level ofliquid in said basin to maintain a liquid seal at each valve in itsclosed position.

References Cited in the le of this patent UNTTED STATES PATENTS

